Mason County, Michigan Natural Disaster Risk
FEMA National Risk Index assessment · MI
Very LowComposite Risk Score
National percentile: 25th
Mason County faces very low composite natural disaster risk (NRI Risk Index score 25.3, 25th national percentile), driven primarily by winter weather and landslide exposure. Expected annual loss across all 18 hazard types is $7M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Mason County is very low, with a National Risk Index score of 25.3 out of 100 — placing it in the 25th national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $459K in expected annual loss and about 28.67 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Very Low risk — $2K in expected annual loss and about 0.13 events per year; and strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at Medium risk — $540K in expected annual loss and about 1.08 events per year. Across all hazards, FEMA estimates $7M in expected annual loss for a population of 29K.
Beyond physical exposure, Mason County has a high social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The federal record bears this out: Mason County has received 9 federal disaster declarations since 1977, including 2 for biological events and 2 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 83 Michigan counties, Mason County ranks #62 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Winter Weather | High | 28.67 / yr | $459K |
| Landslide | Very Low | 0.13 / yr | $2K |
| Strong Wind | Medium | 1.08 / yr | $540K |
| Riverine Flood | Low | 0.39 / yr | $4M |
| Cold Wave | Low | 0.89 / yr | $540K |
| Wildfire | Very Low | 0.00 / yr | $22K |
| Heat Wave | Very Low | 1.47 / yr | $131K |
| Coastal Flood | Very Low | 0.01 / yr | $5K |
| Lightning | Low | 28.80 / yr | $89K |
| Ice Storm | Low | 0.34 / yr | $22K |
| Tornado | Very Low | 0.15 / yr | $283K |
| Earthquake | Very Low | 0.00 / yr | $29K |
| Hail | Very Low | 0.76 / yr | $58K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Mason County has received 9 federal disaster declarations since 1977, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Biological (2), Severe Storm (2), Flood (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| June 1998 | Severe Storm | Severe Storms |
| September 1986 | Flood | Severe Storms & Flooding |
| September 1985 | Flood | Severe Storms and Flooding |
| January 1978 | Snowstorm | Blizzards & Snowstorms |
| March 1977 | Drought | Drought |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Mason County?
Mason County has a composite FEMA National Risk Index score of 25.3 out of 100, placing it in the Very Low category and the 25th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Mason County?
The three highest-rated hazards are Winter Weather (High, $459K EAL), Landslide (Very Low, $2K EAL), Strong Wind (Medium, $540K EAL). These account for most of the county's expected annual losses.
How does Mason County compare to other Michigan counties?
Mason County ranks #62 of 83 Michigan counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Mason County had?
FEMA records 9 federal disaster declarations for Mason County since 1977, most often 2 for biological events and 2 for severe storm events. The most recent was Covid-19 Pandemic, declared in March 2020.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Mason County's $7M EAL is a statistical average, not a guarantee for any specific year or address.